Where are you guys riding at? Death Valley in mid summer? I live and ride in the dez done the mods on my 06 wr450 and run the stock off the shelf stuff. You know the one that on the back of the bottle say open and then pour. On any given weekend I am out riding 3 to 5 hours. I did a 75 mile ride last summer in 114 deg F day and had no problems. I think the only thing I did different than some people was read the part in the manual that said dont sit at idle for prolonged periods. I ride fast trail, moto when I can climb hills play in rocks even ride the dunes. I changed my coolant in Dec to get ready fo rthis year. The key is keep moving and dont sit in the same spot to long.